本文以認知神經科學觀點探討雙語學習的認知歷程、大腦神經生理機制及華人學習英語的認知歷程。首先探討的是第二語言學習是否有關鍵期存在？行為及腦造影研究皆不支持第二語言學習有關鍵期存在。儘管啟始學習年齡確實與第二語言學習有關，但目前的證據僅限於語音，部分證據支持語法，而不存在詞彙知識中。本文也嘗試討論台灣人學習英語的認知處理，研究顯示，至少在聲韻處理方面，母語為中文確實影響第二語言學習者對於英語的學習情形。 This article reviews the cognitive processes and neural mechanisms of second language acquisition of Chinese English learners. The first issue addressed is whether there is a critical period in second language learning Behavioral and brain imaging research do not provide sufficient evidence for this hypothesis. Though there is correlation found between age of acquisition and second language learning, albeit it was in the situation of ESL (English as Second Language). Given that age of acquisition does influence language acquisition, the effect was limited to phonology, while its effect on syntax scarce, and vocabulary not at all English learning in Taiwan is EFL (English as Foreign Language) instead of ESL. Whether the conclusion drawn from ESL can be adequately applied upon EFL needs to be further discussed by examining whether there is a parallel pattern of cognitive processing mechanism and language environment between ESL and EFL. This research also shows that speakers whose mother-tongue is Chinese at least do have some inhibitions with phonology when learning English as a foreign language.